This disclosure is related to shape optimized headers and to methods of manufacture thereof.
Industrial plants such as chemical plants and power generation facilities often employ headers to collect fluids (e.g., steam and/or other vapors). These headers and the associated distribution hardware are always possessed of circular cross-sectional geometries with uniform wall thicknesses. These geometrical attributes are selected because they can easily be manufactured from available pipe, or by rolling and seam welding plates, or by centrifugal casting. Ease of manufacturing dictates the shapes of the header geometry as well as the wall thicknesses.
The FIGS. 1A and 1B depicts a front view and a side view, respectively, of a current commercially available header 100 (also referred to herein as a “comparative header”). As can be seen from the FIGS. 1A and 1B, the header 100 comprises a shell 102 of a uniform circular cross-sectional internal diameter “d” and a uniform wall thickness “t” that is in communication with an array of tubes 104 that enter the header along its length. The shell 102 is operative to collect a fluid that is discharged into the shell via the array of tubes 104.
The shell 102 comprises a first end 106 and a second end 108 that is opposite to the first end 106. The first end 106 is sealed to the outside, while the second end 108 is in communication with an outlet port (not shown) that permits the evacuation of the fluid that is collected in the header 100 to the outside.
In the depiction shown in the FIGS. 1A and 1B, the steam pressure and/or the fluid flow rate into the header 100 is lowest in the array of tubes 104 that are closest to the first end 106 while it is highest in the array of tubes 104 that are closest to the opposite end. The internal diameter “d” of the shell 102 is determined by considering the pressure drop within the shell 102. This is done to ensure that the array of tubes 104 are controlling the resistance in the system. The diameter d of the shell 102 is also calculated in such a manner as to limit frictional losses in the header itself. This internal diameter d then defines the bore of the pipe used to fabricate the shell 102. Since the entire internal diameter is based upon the cumulative flow of the fluid entering shell 102, the header design shown in the FIGS. 1A and 1B is larger than it needs to be, other than at the outlet plane, and consequently uses a larger amount of material than needed for an efficient design. This increases material costs and results in headers that are expensive and occupy more space in the plant than needed.
As more expensive materials are used to manufacture the headers, these old designs may become cost prohibitive. It is desirable to use geometries and wall thickness that enable cost savings, while at the same time reducing maintenance costs and component breakdowns. It is also desirable to produce headers and associated distribution systems that can operate under existing conditions in a plant for time periods that are as long or longer than the currently existing header designs.